No need Dave, one of the guys that rides with us had a spare bolt with him last night (cheers Frank) which saved me a long honk home. So you're not the only one that carries one "just in case", Dave. Glad it didn't go in the middle of Rannoch Moor!
I guess it is a 31.8 I need then, I've had a look at the tubing dimensions on Konaworld.com and the seat tube appears to be round and of constant external diameter so that should be fine.
Kona are indeed lying! If you aren't sure of the size, ask at a Kona dealer what size should fit... I seem to remember there is something slightly weird about seatpost clamp sizing... alternatively take the old clamp with you when you go to buy a new one, she says stating the obvious. I would say though that rather than going for a clamp that you can wind up well tight, you should check whether the seatpost is the right size if it keeps slipping, cos it shouldn't!
Reet, the story from Kona is that most steel Konas need a 29.8 seat clamp and a 28.6 mech as the tube is externally butted. Monkeymetal Konas like mine take a standard 31.8 clamp.
My frame is built for a 27 post and that's what I have (well, a 25 shimmed to 27). If it keeps slipping with a bolt-up clamp I'll try a 27.2 shim next.
I got a 31.8 clamp from Stif last night, it fits but I've not ridden the bike yet so I don't know if it slips or not. It's off a Santacruz so I now have the first part of my Superlight. ;-)
a 31.8 clamp will fit the same frames as a 31.0, a 31.4, a 31.6 etc. There are only three real sizes, and provided you get the one near the size of the last one, it will fit. Bring the old one to the shop, and they'll find the right size for you.
Shimmed posts have a nasty habit of slipping.... I found that the only way i could stop mine was by getting one a size too big, and filing a rough surface onto the inside - though this does scratch your seatpin - it'll end up narrower at the bottom than at the top.
